Tool turret

ABSTRACT

The invention relates to a tool turret, comprising a tool disk ( 1 ), which has at least one tool receptacle ( 7 ) for a machining tool and which is fastened to an accommodating disk ( 51 ), which can be swiveled about a support column that defines a swivel axis into positions in which the particular machining tool is in a working position, a contact surface ( 55 ) being provided on the tool disk ( 1 ), wherein said contact surface can be clamped to an accommodating surface ( 53 ) on the accommodating disk ( 51 ) by means of a clamping device. The tool turret is characterized in that the clamping device has an annular groove on one ( 51 ) of the two components ( 1, 51 ) to be clamped, said annular groove being concentric to the swivel axis and being open radially outside and having at least one inner slanted surface ( 81 ), and the clamping device has at least one compression piece ( 57 ) on the other ( 1 ) component, said compression piece penetrating the annular groove ( 61 ) under compressive force and having a wedge surface ( 79 ), which in interaction with the slanted surface ( 81 ) of the annular groove ( 61 ) produces a force component as a clamping force from the compressive force, which presses the contact surface ( 55 ) and the accommodating surface ( 53 ) against each other.

The invention relates to a tool turret comprising a tool disk, which has at least one tool holder for a machining tool and is fastened to a receiver disk, which can be swiveled around a support column, defining a swivel axis, into positions in which the particular machining tool is in a working position, wherein the tool disk has a contact surface, which can be clamped to a receiving surface on the receiver disk by means of a clamping device.

Tool turrets of this kind are known from the prior art. In the state of the art, which is documented, for example, in U.S. Pat. No. 7,475,463, the receiver disk, to which the tool disk is fastened, forms both a supporting element, at which the tool disk is held for its swivel movements, and at the same time the output-side element of the swivel drive for positioning the respective machining tools into the desired working positions. When such units are in operation, the tool disk, which forms the turret head, is subject to high loads with correspondingly high torques that try to twist the tool disk out of the target position, when, for example, rotary tools for high cutting performances or stationary tools, such as, for example, turning tools for lathe work or the like, are fastened to the tool disk. In order to ensure high quality machining under such conditions, it is necessary to make special arrangements that will guarantee a secure attachment of the tool disk to the receiver disk.

In the state of the art, the tool disk has screw bolt holes in order to screw the tool disk to the receiver disk from the inside of the turret head using machine screws. Such solutions are not completely satisfactory. In addition to the production and assembly costs, a threaded joint between the tool disk and the receiver disk renders it difficult to achieve a safety function that makes it possible to rotate the tool disk with the turret head relative to the receiver disk in case of an emergency, in order to prevent the swivel drive and/or the turret head from being damaged in a so-called “crash case” during the ongoing operations.

Based on the aforesaid, the object of the present invention is to provide a tool turret that is distinguished by a clamping device that is intended for fastening the tool disk to the receiver disk, is easy to build, and guarantees a high degree of operational reliability.

The present invention achieves this object with a tool turret having the features specified in claim 1 in its entirety.

Therefore, one essential feature of the invention lies in the fact that, instead of a threaded joint provided between the tool disk and the receiver disk, the position is secured by generating a compression force between the tool disk-side contact surface and a receiving surface of the receiver disk. In this case, this compression force is generated by means of a wedge effect between an annular groove, which concentrically surrounds the swivel axis and forms an inclined surface, and at least one pressure piece, which penetrates the annular groove under compression force. This pressure piece has a wedge-shaped surface, which in interaction with the inclined surface of the annular groove generates a force component that forms the clamping force.

Not only does the above feature of the invention allow the tool disk to be free of boreholes, it also opens up the advantageous possibility of dimensioning the compression force, generated by way of the wedge effect, between the contact surface and receiving surface in such a way that the resulting frictional locking enables a slippage when a critical threshold value of the torque is exceeded. Therefore, given the ease with which the clamping device can be built, the invention offers the additional advantage that the mandatory safety function is simultaneously fulfilled without having to introduce additional design measures for this purpose.

For the optimal dimensioning of the clamping force which yields the desired frictional locking and is obtained by the wedge effect, there are preferably a plurality of pressure pieces for the interaction with the annular groove.

In especially advantageous exemplary embodiments, the annular groove is formed in a cylindrical outer surface, which is provided on the receiver disk and is concentric to the swivel axis. In this case, the tool disk has a shoulder, which extends over the cylindrical outer surface and on which preferably more than one pressure piece is arranged. At the same time, the cylindrical outer surface of the receiver disk and the cylindrical inner surface of the shoulder of the tool disk form fitting surfaces for centering the latter on the receiver disk.

In especially advantageous exemplary embodiments, the receiver disk is formed by means of a flange-like expansion on the end of a hollow shaft surrounding the support column. In this case, the end-side front face of the expansion that defines a radial plane forms the receiving surface, which can be pressed against the contact surface that forms a radial plane that internally defines the shoulder of the tool disk.

The annular groove can have advantageously a V-shaped cross section; and the respective pressure piece can have a wedge-shaped piece that forms the wedge-shaped surface. Their relative position and dimensions can be chosen in such a way that the wedge-shaped surface interacts with that side wall of the groove that forms the inclined surface for generating the clamping force component.

The arrangement can be configured in such an advantageous way that the respective pressure piece is arranged in a radial borehole, which is provided in the shoulder of the tool disk and which has an internal thread for a threaded joint that generates the compression force. In this case, the pressure piece is made of the actual wedge-shaped piece, which forms the wedge-shaped surface, which interacts with the inclined surface of the groove, and a threaded piece, which can be rotated relative to this wedge-shaped piece and which is a part of the threaded joint. The clamping device, which is designed in this way, is distinguished by an extremely simple design and ease of operability.

The radial borehole can be designed preferably in such a way that it forms an outer threaded section for the external thread of the threaded piece and a non-threaded inner guide section, which forms a fit for guiding the wedge-shaped piece.

With respect to extreme ease of assembly, the arrangement can be configured in such a way that the wedge-shaped piece and the threaded piece are connected together in such a way that they can be rotated, but not detached.

The invention is explained in detail below by means of one exemplary embodiment that is depicted in the drawings. Referring to the drawings:

FIG. 1 shows a center section of the exemplary embodiment of the tool turret according to the invention, with a tool holder of the tool disk, forming the turret head, being in a working position, but without the machining tool, inserted into the tool holder;

FIG. 2 shows a partly broken out section (drawn slightly smaller than a practical embodiment) of just one circumferential section of the tool disk, the associated peripheral region of the receiver disk, and a pressure piece of the clamping device, where these parts are shown in an exploded position relative to each other;

FIG. 3 is a drawing similar to FIG. 2, with the tool disk and the receiver disk being fastened to each other by means of the pressure piece that can be found in the working position; and

FIG. 4 shows an enlarged detail of the region designated as IV in FIG. 3.

In the drawings, the reference numeral 1 denotes a tool disk that forms the main component of a turret head that is designated as a whole as 3 in FIG. 1. The tool disk 1 forms a peripheral annular body 5, which is provided with the tool holders 7, which can range in number, for example, up to 16 tool holders that are spaced apart from each other at regular intervals over the periphery. FIG. 1 shows two tool holders 7, of which one tool holder 7 is in a working position, in which a machining tool, accommodated, as required, if it concerns a rotary tool (not shown in FIG. 1), can be coupled with a drive device 9, which can be engaged and disengaged and is intended for the rotary drive of the rotary tool concerned. The drive device 9 is located in the inner receiving space 11 of the turret head 3; and this inner receiving space is formed between the annular body 5 of the tool disk 1. The module that forms the drive device 9 is rigidly connected, that is, cannot be rotated, to the support column 15 by means of connecting screws 13 (of which just a few are labeled in FIG. 1), whereas the tool disk 1 can be rotated around the swivel axis 17, defined by the support column 15, in order to adjust the working positions. In the swivel position of the turret head 3 shown in FIG. 1, the tool holder 7, which is located at the bottom in FIG. 1, is in alignment with the rotational axis 19 of the motor shaft of the electric motor 21, located in the receiving space 11, for the direct drive of a rotary tool (not illustrated) that is located in the tool holder 7. This motor 21 also forms the drive source for the swivel drive for rotating the tool disk 1 around the swivel axis 17. For this purpose, the motor shaft of the electric motor 21 can be connected to an intermediate gear having gearwheels 23 and 25. The gearwheel 25 meshes with the Hirth coupling on a gear rim 27, which is located, as the flange-like expansion, on the end of the hollow shaft 29, which surrounds coaxially the support column 15. The hollow shaft 29 forms the input shaft for a Wolfrom planetary gear 31, which is mounted on the support column 15 so as to be axially offset relative to the turret head 3. This planetary gear has, according to the known Wolfrom system, at least one planet wheel 33, which meshes with the internal teeth 35 and 37 that are formed on a housing part 39 that is stationary with the support column 15 or a rotatable housing part 41. At the same time, the internal teeth 37 and 35 have a slightly different number of teeth, so that, according to the Wolfrom principle, the rotatable housing part 41 has a much lower speed compared to the input speed of the hollow shaft 29. This greatly reduced speed that is appropriate for the swivel drive of the tool disk 1 is transferred to the receiver disk 51 by means of an output-side hollow shaft 43, which also surrounds coaxially the support column 15. This receiver disk is attached on the end of the hollow shaft 43 in the form of a collar-like expansion and forms the receiving surface 53 that can be clamped with the contact surface 55 onto the tool disk 1.

Further details of the clamping device for clamping the contact surface 55 of the tool disk 1 onto the receiving surface 53 are explained below with particular reference to FIGS. 2 to 4. FIG. 2 is a sectional view of the peripheral sections of the tool disk 1, without the associated structural components, and the receiver disk 51 in an exploded position relative to each other, and a pressure piece 57 as a component of the clamping device. This clamping device has a circumferentially continuous annular groove 61 with a V-shaped cross section in a radially external cylindrical outer surface 59 of the receiver disk 51. This annular groove interacts with the pressure pieces 57 for the clamping operation. Of these pressure pieces, two pressure pieces 57 are shown in FIG. 1; and FIGS. 2 to 4 show in each instance one pressure piece 57. For each of these pressure pieces 57, the tool disk 1 has radial boreholes 63, which are located in a shoulder 65 of the tool disk 1. In the fastened state (see FIG. 3), the shoulder extends over the cylindrical outer surface 59 of the receiver disk 51.

FIGS. 2 and 4 show distinctly that the pressure pieces 57 are made in two parts and have a wedge-shaped piece 67 and an actuating element in the form of a threaded piece 69 for the interaction with the annular groove 61. The radial boreholes 63 have an outer threaded section 71 for the respective threaded piece 69 and an internal guide section 73 for the wedge-shaped piece 67. This internal guide section forms a fit, in which the wedge-shaped piece 67 is guided in a radially movable manner. FIG. 4 shows distinctly that the threaded piece 69 and the wedge-shaped piece 67 can be rotated relative to each, but are connected together in a captive manner by means of a clip-like snap connection 75 (FIG. 4).

FIGS. 3 and 4 show the fastening or clamping state, in which the wedge-shaped piece 67 is pressed with a wedge-shaped surface 79 against an inner wall of the annular groove 61 that forms an inclined surface 81 when the threaded piece 69 is tightened by means of a hexagon socket 77. As a result, a force component is generated that tries to pull the wedge-shaped piece 67 and with it the tool disk 1 to the right in the drawing and tries to pull the receiver disk 51 to the left in the drawing, so that the contact surface 55 of the tool disk 1 and the receiving surface 53 of the receiver disk 51 are clamped together. The number of pressure pieces 57, distributed over the periphery, and the tightening torque of the threaded pieces 79 is chosen in conjunction with the geometry of the wedge-shaped surfaces 79 on the wedge-shaped pieces 67 and the geometry of the inclined surfaces 51 of the annular groove 61 in such a way that the resulting frictional locking between the contact surface 55 and the receiving surface 53 can be adjusted to an optimal value, so that on exceeding a critical torque, acting between the tool disk 1 and the receiver disk 51, the wedge-shaped pieces 67 slip in the annular groove 61. In this way, a simple design feature offers a safety device that prevents damage from occurring in the event of a “crash” during ongoing operations, for example, in the event that the turret head 3 is jammed when the swivel drive is activated. When the shoulder 65 of the tool disk 1 extends over the cylindrical outer surface 69 of the receiver disk 51 in the clamping or fastening state, the outer surface 59 and the cylindrical inner surface of the shoulder 65 form fitting surfaces for the mutual centering of the tool disk 1 and the receiver disk 51. At the same time, the front face of the receiver disk 51 that forms the receiving surface 55 and the assigned contact surface 53 on the tool disk 1 form fitting surfaces for the axial positioning. In order to lock, in a form fitting manner, the receiver disk 51 and with it the tool disk 1 into the respectively adjusted swivel positions, a locking device is provided in the form of a sliding bolt body 85, which can be displaced hydraulically, in order to engage and disengage a Hirth coupling 87 provided between the bolt body 85 and the receiver disk 51. 

1. A tool turret comprising a tool disk (1), which has at least one tool holder (7) for a machining tool and is fastened to a receiver disk (51), which can be swiveled around a support column (15), defining a swivel axis (17), into positions in which the particular machining tool is in a working position, wherein the tool disk (1) has a contact surface (55), which can be clamped to a receiving surface (53) on the receiver disk (51) by means of a clamping device, characterized in that the clamping device has an annular groove on one (51) of the two components (1, 51) to be clamped, said annular groove being concentric to the swivel axis (17) and being open radially on the outside and having at least one inner inclined surface (81); and the clamping device has at least one pressure piece (57) on the other (1) component, said pressure piece penetrating the annular groove (61) under compression force and having a wedge-shaped surface (79), which in interaction with the inclined surface (81) of the annular groove (61) generates a force component as a clamping force from the compression force, and this clamping force presses the contact surface (55) and the receiving surface (53) against each other.
 2. The tool turret according to claim 1, characterized in that the annular groove (61) is formed in a cylindrical outer surface (59), which is provided on the receiver disk (51) and is concentric to the swivel axis (17); and that the tool disk (1) has a shoulder (65), which extends over the cylindrical outer surface (59) and on which preferably more than one pressure piece (57) is arranged.
 3. The tool turret according to claim 2, characterized in that the receiver disk (51) is formed by means of a flange-like expansion on the end of a hollow shaft (43) surrounding the support column (15); and that the end-side front face of the expansion that defines a radial plane forms the receiving surface (53), which can be pressed against the contact surface (55) that forms a radial plane that internally defines the shoulder (65) of the tool disk (1).
 4. The tool turret according to claim 2, characterized in that the cylindrical outer surface (59) of the receiver disk (51) and the cylindrical inner surface of the shoulder (65) of the tool disk (1) form fitting surfaces for centering the latter and the receiver disk (51).
 5. The tool turret according to claim 1, characterized in that the annular groove (61) has a V-shaped cross section; and the respective pressure piece (57) has a wedge-shaped piece (67) that forms the wedge-shaped surface (79); and their relative position and dimensions are chosen in such a way that the wedge-shaped surface (79) interacts with that side wall of the groove (61) that forms the inclined surface (81) for generating the clamping force component.
 6. The tool turret according to claim 2, characterized in that the respective pressure piece (57) is arranged in a radial borehole (63), which is provided in the shoulder (65) of the tool disk (1) and which has an internal thread for a threaded joint that generates the compression force.
 7. The tool turret according to claim 5, characterized in that the pressure piece (57) is made of the wedge-shaped piece (67) and a threaded piece (69), which can be rotated relative to this wedge-shaped piece and which forms a part of the threaded joint.
 8. The tool turret according to claim 7, characterized in that the radial borehole (63) has an outer threaded section (71) for the external thread of the threaded piece (69) and a non-threaded inner guide section (73), which forms a fit for guiding the wedge-shaped piece (67).
 9. The tool turret according to claim 7, characterized in that the wedge-shaped piece (67) and the threaded piece (69) are connected together in such a way that they can be rotated, but not detached. 